Regional security monitoring systems often contain detectors that monitor the open/closed state of doors and windows. The vast majority of known non-contact door and window detectors consist of a magnet mounted on the door or window and a reed switch in a housing mounted on the door frame or window frame. This type of detector is generically referred to as a “magnetic contact”. The problem with the magnet/reed switch combination is that the sensing range (gap between the pair) is limited to ½ to 1 inch for standard magnetic contacts and up to 3 inches if the design contains very large/expensive magnets on the door and/or a “helper magnet” in the sensor housing. These gaps only apply on non-ferromagnetic materials (wood). The gap for most sensors is reduced to ½ that noted when mounted on ferromagnetic materials such as steel. This means the maximum gap available on steel in the industry today is on the order of 1.5 inches.
Users would like to achieve a gaps on steel greater than 1.5 inches and up to 4 inches. They want to install door detectors on perimeter fences, sheds and pool gates. These doors have large gaps and the doors and frames are often made of steel. Also, as these are typically outdoor detectors, the users would like these to be wireless and not require battery replacement for five years.
Additionally, a given magnetic contact (magnet/reed switch pair) will have a specific distance at which the detector will indicate the door is open. There is no adjustment capability in these units. Therefore, if an installer has some doors and windows that he would like to set to alarm at a small gap and others like pool gates that he would like to set for large gaps, then he must carry two different products. Users would like a door window detector that can be set for small gaps and large gaps with a minimum of field adjustment and preferably no physical adjustment at the sensor.
High Security (Defeat Resistant) Magnetically Actuated Contacts have been in the Intrusion Security market place for a number of years. These are typically in the form of magnetically balanced contacts where a switch housing contains multiple form C reed switches and multiple magnets. In the absence of the door mounted magnet assembly, each reed switch in the housing is actuated by a corresponding magnet in the housing. When the door mounted magnet assembly which contains multiple magnets comes into proper position, the magnetic field at each reed switches is cancelled out (balanced) allowing each reed to be in the un-actuated state. If the door mounted magnet assembly gets too close or too far away, at least one reed switch in the switch housing will actuate causing an alarm. Manufacture of this type of switch is highly labor intensive as the positions of the magnets and reed switches must be massaged due to tolerances to get the “balance” just right. In known products, one of the issues has been that the installer must be very careful to precisely set the gap between the switch housing and the magnet housing. Too small or too large and the switch will go into alarm. Although quite difficult to defeat, one cognizant of the design and armed with an identical door mount magnet assembly does have the possibility of defeating a high security contact. It takes significant practice but it can be done. The high end market, banks, nuclear facilities, military contractors and the military, is asking for a virtually defeat proof contact.
Most professional security manufacturers strive to have their products meet the requirements set in the standards published by the governing compliance agencies. The requirements for contacts sold in the Americas are published in UL 634. The requirements for contacts sold in Europe are covered in EN50131-2-6. The requirements set for the highest grade or level contacts in each standard are intended to provide sufficient safe-guards against intruders that are assumed to be highly intelligent, highly skilled in the detector design, and have attempted to defeat similar product. Products passing these requirements are intended for use in high security installations such as military and nuclear facilities. In October of 2007, UL published requirements for a higher grade of High Security contact, UL 634 Level 2. The requirements for Level 2 specify many more and more intricate attacks on the sensor which High Security Contacts on the market at that time could not meet. In September 2008, Europe published requirements for 4 grades of magnetically actuated switches in EN 50131-2-6 with Grade 1 having the least stringent requirements and Grade 4 being the most stringent. The Honeywell 968XTP is certified to the requirements of the second highest grade, Grade 3 but does not meet the requirements of the highest grade, Grade 4. The requirements state that Grade 4 switch products must have a minimum of 8 match-coded-pairs of switches/door magnets where a given switch assembly can only function with one of the at least 8 different magnets.
Using the existing approaches, this would mean a minimum of 8 different SKU's for one model number. Producing a product line with 8 match coded pairs could be extremely labor intensive. In addition, the number of parts for a product that will function singularly with 8 match-coded-pairs would increase significantly to account for the additional magnets and reeds that would be required to satisfy this requirement.